Shipping case for cartons or containers

ABSTRACT

A shipping case for fragile product-filled cartons is made up from a rectangular sleeve of corrugated fiberboard having open ends and having the corrugations thereof running between the open ends. A plurality of cartons are stacked in rectangular configuration in the sleeve and occupy the entire volume of the sleeve, with exposed carton faces forming a substantially planar surface at both ends of the sleeve. Heat shrinkable transparent film in the form of a band is disposed around the open ends of the fiberboard sleeve and around at least two opposite walls of the sleeve, and is shrunk, in order to contain the sleeve and cartons together as an integral unit, thereby providing a shipping case without end flaps.

United States Patent [191 Richardson Nov. 11, 1975 SHIPPING CASE FOR CARTONS OR CONTAINERS Larry A. Richardson, Battle Creek, Mich.

Assignee: Kellogg Company, Battle Creek,

Mich.

Filed: July 30, 1973 Appl. No.: 384,082

Inventor:

References Cited UNITED STATES PATENTS FOREIGN PATENTS OR APPLICATIONS 12,784 5/1933 Australia 206/45.33

Primary Examiner-William T. Dixson, Jr. Attorney, Agent, or FirmGary, .luettner, Pigott & Cullinan {5 7 ABSTRACT A shipping case for fragile product-filled cartons is made up from a rectangular sleeve of corrugated fiberboard having open ends and having the corrugations thereof running between the open ends. A plurality of cartons are stacked in rectangular configuration in the sleeve and occupy the entire volume of the sleeve, with exposed carton faces forming a substantially planar surface at both ends of the sleeve. Heat shrinkable transparent film in the form of a band is disposed around the open ends of the fiberboard sleeve and around at least two opposite walls of the sleeve, and is shrunk, in order to contain the sleeve and cartons together as an integral unit, thereby providing a shipping case without end flaps.

5 Claims, 4 Drawing Figures US. Patent Nov. 11, 1975 SHIPPING CASE FOR CARTONS OR CONTAINERS BACKGROUND OF THE INVENTION Rectangular filled cartons are normally shipped in conventional closed fiberboard cases made up of corrugated material and having overlapping flaps at both ends. in the case of food and other products, the cases must be strong enough to withstand usual handling and stacking forces and must be sealed to protect the contents from contamination, injury, and tampering. Upon arrival at the retail outlet, the cases are cut open and discarded. andthe individual cartons are price tagged and displayed on shelves. The cost of the case and the expense of its'disposal add to the'cost of the product in the carton. As the cases are cut open, several of the inner containers are sometimes cut and must be discarded. I

The use of polymeric heat shrinkable films for the packaging of materials is well known and is described in the following US. Pat. Nos. 3,219,183: 3,058,273: 2,711,346; 3,416,288; 3,338,406; 3,050,402; 3,198,327; 3,447,675 and 3,694,995. The prior art generally deals with heat shrinkable materials disposed around a plurality of rigid or hard objects. such as steel cans, in order to hold the objects together as a unit package, either in a spaced or contiguous relationship. One problem with such packages resides in the difficulty of applying printed information to the exterior polymeric surface. Also well known are corrugated trays in combination with a shrinkable film to hold objects thereon in a stacked relationship. A problem with such arrangement is that the vertical strength of the package is limitedto the strength of the stacked obects.

I SUMMARY OF THE INVENTION In accordance with the present invention, 1 have discovered an inexpensive method for packaging a plurality of filled rectangular paperboard cartons. which totally eliminates the need for a. conventional shipping case having overlapping end flaps, thereby significantly reducing the material cost of the case.

The conventional case is replaced with a rectangular sleeve or tube having open ends and no end flaps. The sleeve is preferably composed of corrugated material having the corrugations running from one open end to the other. The sleeve is sized such that a plurality. of rectangular cartons, when compression packed in contiguous fashion in the sleeve, completely fill the volume of the sleeve with outwardlyfacing walls of the cartons. presenting a substantially flat surface at the open ends of the sleeve. A band-of transparent heat shrinkable polymeric filmis then; disposedaround theopen ends of the sleeve and over two .opposite walls of the sleeve and is shrunk by application of heat to form a unitary case, the ends of whichare formed of the carton surfaces and thermoplastic film.

When the case is constructed properly, the vertical compressive or end strength is unexpectedly superior to that of conventional filled cases. thereby enabling, if

desired, the use of lower weight packing materials with ,attendant cost savings. The improved end strengthis due to the combined strength of the cartons and the corrugated sleeve. Compression packing of the cartons in the corrugated sleeve results in the best possible alignment of all load bearing members, particularly the. individual cartons. The cartons thus contribute to end strength to a greater degree than do the cartons in a conventional case having flaps.

There is another reason for strength improvement in the case of the present invention. In the assembly of a conventional corrugated case having end flaps. it is virtually impossible to maintain the case in a square configuration as the flaps are being glued closed. Any skewing of the rectangular base will also result in a concave configuration in the planes of the flaps. The result is that the highest portion of the concave configuration will pick up the stresses from an external load prematurely. and cause premature fatigue and failure. thereby detracting from the optimum theoretical strength levels. The improved case construction of the present invention does not employ flaps and is more flexible. thereby affording the unique ability to simultaneously pick up an external force across the maximum bearing area and minimizing fatigue or damage due to isolated force levels.

Since the cartons are visible through the transparent overwrap, there is less likelihood that the cartons will be damaged or cut when the case is opened. as compared with conventional cases having overlapping flaps at the ends. The fiberboard sleeve presents an excellent printing surface and for this reason is superior to the packing of a plurality of containers solely by means of a shrink or other flexible or. transparent wrapper.

Other conveniences and advantages of the present invention will become apparent from the following detailed description.

THE DRAWlNGS DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates the three components which comprise the shipping case of the present invention. namely a rectangular corrugated sleeve IO having opposite open ends 12, a plurality of rectangular fiber board cartons 14 adapted to be packed snugly in the sleeve. anda heat shrinkable band or tube 16 of sufficient size to slip over and cover the open ends and a pair of opposite sides of the'sleeve. The band or tube normally will be comprised of integrally extruded tube stock or flat sheetstock formed into a tube. or a flat sleeve may simply be wrapped around the ends of the fiberboard sleeve.

The sleeve 10 may be constructed of suitable sheet stock having compressive strength in the direction from open end to open end thereof. such as vertically oriented conventional corrugated fiberboard wherein a corrugated or fluted sheet is bonded between a pair of spaced walls. Opposite ends of the fiberboard sheet are connected to. form a tube, and the tube is shaped with four corners running parallel to the flutes. The sleeve 10 thus has four walls connected in rectangular fashion, and one or more walls may carry desired printed information, such as product indentification or coding. Although singlewall corrugated will normally provide sufficient strength, double and triplewa ll corrugated boards may also be employed.

The sleeve I0 is of a size which is adapted to receive a plurality of filled rectangular cartons 14 in a stacked or nested relationship within the sleeve. The cartons. which would normally be made up from a flexible fiberboard material. are preferably equi-sized and have substantially flat side and conventional flappcd end surfaces. The cartons are arranged in a contiguous array and when properly assembled. as shown in FIG. I. together define I a rectangular solid having a volume which is substantially equal to the volume between the open ends of the sleeve. The solid thus defined'by the carton arrangement has six outwardly facing and substantially flat and planar surfaces. which are discontin uous only at the juncture between adjacent cartons. Four of the exposed surfaces of the arrayed cartons are placed in full contact with the respective interior walls of the sleeve: the other two exposed surfaces of the array occupy the open ends of the sleeve and are substantially level with the edges at the open ends. The other unexposed surfaces of each carton are in full contact with a corresponding surface of an adjacent carton.

As shown in the figures. the sleeve and cartons therein define a structurally solid package. with two opposed end surfaces being made up of the outwardly facing carton surfaces. In order to hold the cartons in the sleeve and to increase the integrity of the assembly. the shrinkable band is wrapped or otherwise provided around the sleeve so as to overlie the open ends. and is then shrunk down onto the sleeve (in the-direction of the corrugations) to retain the cartons in a contiguous relationship. Due to the compressive strength of the corrugations ofthe sleeve 10, the shrinking of the film down onto the cartonsis controlled to provide a firm but not excessive holding force. The resultant combination of the corrugated sleeve I0, the cartons Hand the band 16 are thus combined to provide a. uniquely strong case having undistorted walls and high degree of flexibility in comparison with conventional cases.

The band 16 is preferably in the form of a tubular section of transparent. heat shrinkable thermoplastic material. whichtube has a large enough diameter to fit over the open ends of the sleeve and is .sufficiently long to completely cover the open ends with extra material at both sides. As shown in FIGS. 2, 3 and 4, the material is heat shrunk over the four corners and end edges of the sleeve. such that the material completely overlies the open ends and a pair of opposed walls of the sleeve. The edges of the material lap over onto the other op} posed pair of surfaces of the sleeve and terminate in the form of an oval window at 18. The band 16 may be conveniently made up from flat sheet material by joining and heat sealing opposite edges of an appropriate size flat sheet.

The' heat shrinkablen aterial described herein may comprise any of the uniaxially or biaxially oriented polymeric films which upon application of heat are shrunk to a decreased surface area. Suitable films include oriented polyolefinic films such as polyethylene. polypropylene. polyisopropylethylene and polyisobutylethylene. Other exemplary films are polyvinyl chloride polyethylene terephthalate. polyethylene-2,6-naphthalate. polyhexamethylene adipamide, and the like, as well as polymers of alpha mono-olefinically unsaturated hydrocarbons having polymer producing unsaturation such as is present in butene, vinyl acetate, methyl acrylate, Z-ethyl hexyl acrylate. isoprene. butadiene acrylamide. ethyl acrylate N-methyl-n-vinyl acet- 4 amide and the like, This list is illustrative of the types of polymeric films known in the art and is not intended to be exhaustive of all heat shrinkable films. since many others are known which may be successfully employed.

The film of the preferred embodiment is a polyolefin and preferably biaxially oriented polyethylene. The thickness is not critical and may vary between at least I.( to It) mils. The material is preferably transparent to reveal the markings on the sleeve and the labels or printing on the cartons facing the open ends. The film also reduces penetration of moisture vapors into the case and allows for the insertion of information panels under the film.

Variouspossible arrangements of the cartons within the vsleeve are shown in FIGS. 2, 3 and 4. It will be noted that the completed case is intended to be shipped and stored with the corrugated flutes disposed vertically. in order to withstand forces imposed on the case when a plurality of cases are stacked. It is also important that the largest and hence weakest panels of the cartons be arranged or orientated to receive the maximum degree of protection from the sleeve and film. especially since the case may be subjected to lateral grip ping forces as well as compressive stacking forces during loading and storage. The arrangements shown in FIGS. 2, 3 and 4 are designed to provide such protection. as will now be described.

. As shown in FIGS. 1 and 2, the cartons may be arrangedin the sleeve with their largest panels facing the open ends of the sleeve or perpendicular to the sleeve corners. In this manner. the larger panels are protected against deflection by the relatively rigid flutes of the corrugated sleeve. This arrangement is particularly beneficial to allow display of the cartons in the retail outlet after the transparent overwrap has been partially or entirely removed. I

In the arrangment shown in FIG. 4, the side surfaces of the cartons are arranged to face outward from the open end of the sleeve and the larger carton panels and ends are oriented parallel to respective pairs of opposed walls of the sleeve..ln order toprotect the larger panels. the polymeric band is applied in such a manner that it completely overlies the sleeve walls in contact with the larger panels, in order to impart additional support and protection thereto.

Another suitable arrangement is shown in FIG; 3, in which four rows of cartons are provided with the ends facing'outward, and the larger carton panels face and are protected by the sleeve and "film laminate. and the smaller side surfaces face the other opposed walls of the sleeve, which are not protected "entirely by the transparent overwrap. This arrangement is desirable to facilitate the application of price markings to the top of thecarton after the transparent wrap has been removed from either one or both ends of the case.

It has been found that the case of the present invention. when properly packed and compared with a conventional case of the same size having the conventional flaps. provides a top to bottom compressive strength improvement in the order of 25 percent and the case has excellent handling characteristics. Moreover, elimination of the flaps and the folding and pasting operation provides for about a 50% reduction in cost. Compression packing of a sleeve in accordance with the present invention improves the strength contribution of the cartons and provides for better squareness that improves stability for storage and handling.

The following example is given in further illustration of the present invention.

The strength of the shipping ease of the present invention was compared to the strength of a conventional singlewall corrugated case having flaps. The respective cases were of the same size, and equal numbers of identical cartons containing ready-to-eat cereal were packed in each case in an array similar to that shown in FIG. 3. The case of the present invention was made up from a sleeve of single ply corrugated board of the same specifications as the board in the conventional case, and the wrap was made up from a 3 mil. tube of biaxially oriented polyethylene. The open ends of the carton-filled tube were covered with the wrap as shown in FIG. 1 and the wrap was shrunk to the maximum extent possible, within the control provided by the sleeve, by application of heat. Ten cases of each type were prepared and subjected to compression tests on all three axes. The following table illustrates the test results.

Compression Strength The terms TB, SS and EE designate top to bottom. side to side (i.e., from upper right to lower left in FIG, 3) and end to end (from upper left to lower right in FIG. 3) respectively. The end to end strength measurement was taken in the direction normal to the larger carton panels, and the side to side strength measurements correspond to compression in the narrow dimension of the carton, while TB designates compression parallel to the flutes or corrugations of the sleeve.

The top-to-bottom strength is the most critical, since this value determines the extent of permissible vertical stacking. It may be seen that the top to bottom strength of the shipping case of the present invention was 28% greater than that of the standard case. The side to side strengths were essentially the same. The conventional case exhibited superior end to end strength, which was due, primarily, to the presence of the flaps. The loss in end to end compression strength, however, is not critical.

In actual field tests, where the cases were subjected to conventional handling, including side clamping, the case of the present invention was found to have more than adequate strength both side to side and end to end. The significant increase in top to bottom strength was a substantial and unexpected plus, permitting a increase in stacking height without any offsetting 6 disadvantages. And at the same time. costs of the case were reduced by I claim:

1. A shipping case adapted to be stacked vertically upon and under other such cases and consisting essentially of the combination of i a. a continuous rectangular sleeve of single or multiple wall corrugated fiberboard, said sleeve being disposed vertically and having an open top and bot tom, with the corrugations of said sleeve extending vertically between said top and bottom parallel to the four corners of said sleeve.

b. a plurality of crushable rectangular cartons com pression packed in firm contiguous engagement with one another and the four vertical walls of said sleeve, said cartons filling the entire volume of said sleeve and having upwardly and downwardly facing surfaces forming planar surfaces flush with the top and bottom edges of said sleeve, and

c. a separate continuous sleeve of heat shrinkable polymeric material applied horizontally around and heat shrunk onto said corrugated sleeve, said heat shrunk sleeve including continuous walls overlying and engaging the upwardly and downwardly facing planar surfaces of said cartons at the top and bottom of said corrugated sleeve, and overlying a pair of opposed walls and all eight corners, and at least partially overlying the other pair of opposed walls of said corrugated sleeve, 7

the combination of said cartons and said sleeves constituting an integral case in which corresponding vertical walls of the cartons are aligned and are parallel with one another and the walls of said corrugated sleeve, and in which the strengths of said cartons and said corrugated sleeve are combined to provide increased vertical stacking strength.

2. The shipping case of claim 1 wherein said cartons have a pair of opposed surfaces which are larger than the other surfaces thereof, said larger surfaces facing the top and bottom of said corrugated sleeve and forming said planar surfaces.

3. The shipping case of claim 1 wherein said cartons have a pair of opposed surfaces which are larger than the other surfaces thereof and wherein said larger surfaces face the opposed walls of said corrugated sleeve which are fully covered by said heat shrunk sleeve.

4. The shipping case of claim 1 wherein the top and bottom of each carton face the top and bottom of said corrugated sleeve and form said planar surfaces.

5. The shipping case of claim 1 wherein side surfaces of each carton face the top and bottom of said corrugated sleeve and form said planar surfaces.

=l 1 l l 

1. A shipping case adapted to be stacked vertically upon and under other such cases and consisting essentially of the combination of a. a continuous rectangular sleeve of single or multiple wall corrugated fiberboard, said sleeve being disposed vertically and having an open top and bottom, with the corrugations of said sleeve extending vertically between said top and bottom parallel to the four corners of said sleeve, b. a plurality of crushable rectangular cartons compression packed in firm contiguous engagement with one another and the four vertical walls of said sleeve, said cartons filling the entire volume of said sleeve and having upwardly and downwardly facing surfaces forming planar surfaces flush with the top and bottom edges of said sleeve, and c. a separate continuous sleeve of heat shrinkable polymeric material applied horizontally around and heat shrunk onto said corrugated sleeve, said heat shrunk sleeve including continuous walls overlying and engaging the upwardly and downwardly facing planar surfaces of said cartons at the top and bottom of said corrugated sleeve, and overlying a pair of opposed walls and all eight corners, and at least partially overlying the other pair of opposed walls of said corrugated sleeve, the combination of said cartons and said sleeves constituting an integral case in which corresponding vertical walls of the cartons are aligned and are parallel with one another and the walls of said corrugated sleeve, and in which the strengths of said cartons and said corrugated sleeve are combined to provide increased vertical stacking strength.
 2. The shipping case of claim 1 wherein said cartons have a pair of opposed surfaces which are larger than the other surfaces thereof, said larger surfaces facing the top and bottom of said corrugated sleeve and forming said planar surfaces.
 3. The shipping case of claim 1 wherein said cartons have a pair of opposed surfaces which are larger than the other surfaces thereof and wherein said larger surfaces face the opposed walls of said corrugated sleeve which are fully covered by said heat shrunk sleeve.
 4. The shipping case of claim 1 wherein the top and bottom of eaCh carton face the top and bottom of said corrugated sleeve and form said planar surfaces.
 5. The shipping case of claim 1 wherein side surfaces of each carton face the top and bottom of said corrugated sleeve and form said planar surfaces. 